No desire for sex, he thinks I’m cheating

I haven’t had sex with my boyfriend in 6 months and it’s because I have zero desire for sex ever since I became pregnant and I’m 7 months now. He says he asked aunt for advice and he said she said it’s because I’m going elsewhere... WTF?!?!

Thing is I know for a fact he did not ask his aunt that. I’ve been around them for quite some time and there’s no way he would’ve asked her that. She would have most definitely seen that as disrespectful. Why would he even make that up?! Why would he think I’m having sex with someone else while I’m pregnant WITH HIS CHILD!? How disgusting is that?!

‼️Edit: Okay, i see an assumption in the comments because i didn’t state that we talked about it and WE HAVE! He’s not suppose to think that I’m cheating. 🤦🏽‍♀️ WE HAVE TALKED ABOUT IT SEVERAL TIMES! He acted as if he understood but I still got accused.‼️